Rotary



Oct. 9, 1934. v. W. ZILEN 319976,057

ROTARY Original FilecTMay 27. 1925 3 Sheets-Sheet 2 ma. 9, w34.. V, wt EN www5? ROTARY 3 Sheets-Sheet 3 Original Filed May 27, 1925 Patented Oct. 9, 1934 UNITED STATES PATENT OFFICE ROTARY "SIG Application Mey 27, 1925, sex-iai Nel 33,267 Renewed March 11, 1933 33 Claims.

This invention relates to hydraulic rotary drilling machines and hasior its principal object the provision of a device of the type in which the parts are so designed ,that not only are certain necessary operations rendered more convenient but the life of the rotary Ais greatly increased.

A specic object of the invention is the prom vision ot means for freely lubricating the gears and bearings of the rotating parts while at the same time providing means for guiding the gritcarrying mud fluid away from the lubricated parts and directly to the drilled hole. A further object of the invention concerns the provi- 1 sion of improved means for facilitating the screw- .ing and unscrewing of the joints of the string without danger of unscrewing a section below the door level.

Still further objects of the present invention concern the general improvement of specific details of the device in order that the rotary may be more satisfactory in practice, such further objects being set forth particularly in the description and claims following.

In the rotary system of drilling for oil, a vertical drill-stem. carrying at itsy lower end the drill'pipe with its cutting bit, is secured to the horizontally revolving table in such a manner as to cause the drill-stem to revolve with the table,

the latter being so mounted as to provide free rotation. Hoisting mechanism, usually located to one side of the derrick and generally secured to the derrick oorand frame,- raises and lowers the drill-stem as the drilling progresses. The

5 drill-stem'is hollow, as is the pipe, and the cutting bit also has a hole drilled through it to form a clear passage from top of stern, pipe and bit.

A mud iluid is pumped through the drilling string and is discharged at the point of cutting 0 et the bottom ef the wen inte the space between the drill-pipe and the walls of the well. This mud, then, together with cuttings of the strata, and other gritty matter rises to the top of the well and in so doing, plasters up the walls of the well by the rotative action of the drill-pipe,

shutting ot! water or gas andl prevents, to a certain extent, caving of the walls of the well. Surplus of this mud and sand laden fluid overflows the well and returns into almud pit to be pumped back forming a continuous 'ow. In ordinary practice this mud generally finds its way into the unprotected machine parts and wears them out by grinding.

The drilling string is suspended from a hoisting teekie in the aerriek and is lowered as the drinsafety and durability. In the ordinary form of (Cl. Z55-23) ing goes'on deeper until the top of the stem is too lowfor continuation. 'The drilling string is then raised, the drill-pipe disconnected from the .lower end of the stem and a new section of o pipe is added, making the drilling string longer, after which the drilling operation is started again. When it is necessary to change the cutting bit, the entire drilling string has to be lifted out of the well section by section until the bit is reached, after which, all the joints must be screwed together section by section, It is this screwing and unscrewing of drill-pipe joints that lead to a consideration of eicient and rapid methods by which the operation may be eiected. In the ordinary form of rotarygof this type the horizontal table, having teeth on' the under side radiating around the edge of the table and forming a bevel gear which meshes with the driving pinion, is entirely exposed to mud and dirt and is a source of danger to life and limb of men working around the machine, and furthermore the effect of the mud and sand reduces the eihciency of the rotary and lowers its factor of rotary of this type there is no provision for lubrio eating the teeth of the gearing except by application by hand; if that is done, then it is worse than if the teeth were left dry, because the sand and mud sticking to the greasy gearing wears it that much faster.

In the usual rotary of this type the provision for screwing and unscrewing joints is ineilicient, slow and complicated. The ordinary types of rotary of this type using rings for gripping circular drill-stems are not satisfactory, for the reason that the gripping surface between the rings and stern is often only a line contact, sliding and cutting around the pipe without turning it and besides such devices are generally very clumsy and require hand adjustment for gripping operation.

Other devices have superseded the ordinary ring gripping devices, but they can be used only for drill-stems having non-circular section. Such drill-stems are generally made of rolled stock requiring expensive machining. A hole must be drilled through the entire length of the drill-stem Whose length varies anywhere from twenty to fifty feet, which hole often runs out of center resulting in a big loss of material and machine labor.

In the combination illustrated in the present disclosure the rubbing surfaces of gear teeth including a driving pinion are entirely housed in and are running in oil while the anti-friction Iso bearings are partially submerged in an oil bath. The provisionfor screwing and unscrewing the pipe joints is, as will be described in detail later, efficient, economical 4and comparatively simple of construction. The drill-stem gripping device is automatic and effective and cariche/used for gripping stems made of ordinary pipe which section is the most economical.

Figure 1 is a plan view, partly in section thru the preferred form of the invention.

Figure 2 is a'. longitudinal vertical section.

Figure 3 is a transverse vertical section through the pinion shaft and showing the table inelevation.

Figure 4 is an end view.

Figure 5 is a radial, vertical section thru a somewhat simpler form of table.

Figure 6 is a radial section through a further modication.

The base 10 is` pivoted on a plurality of skids 11 so that the [axis of the table is directly over the hole to bedrilled.` 'I'hecentral opening of the base is'preferjably cylindrical rhaving a wall 12 which engages with arotatirlgflt'the skirt 14 of the drive ring 20 `bet`vveen'-which and 'a shoulder or seat 17 of thebaseis, an antif-frictionjbearing preferably of the roller type shown, as the weight of the parts morneon 'the rollers'y 18 is at times veryv considerable;

fluid seeping' between the'gear and ringfrom passing toward the gear teeth.

' The drive ring 20 at its outer peripheral edge supports a gear ring 22 to which is secured, as by f with the surface 74 of the drive ring, both of these the bolts 23, an annular. gear 24. It will be noted that the gear members canbe rotated as a whole with respect to the drive ring'under certain circumstances and that there is sliding flt between the gear and drive elements on the surfaces 26,

27 and 28. The gear, and consequently the drive ring, is held down to the base by an annular member or hold-down ring secured to the base by means of bolts 31 and adjusted toproper height with respect thereto by means of shims 32, The actual bearing surface between the holddown ring and the gear lis at 33 although Lmake the vertically cylindrical bearing 34 as snug as possible and to avoid abrasion caused by seepage of the mud and sand fluid to the gear or to the bearing surface 33 I provide an annular flange- 36 on the hold-down ring and above this I locate a mud guard 37 having an outwardly flared bell-like apron 38 clearing the upstanding flange 36 and. directing the mud carrying fluid to the side of the hold-down ring and base.

The gear 24 is driven by means of a pinion 40 fast on a shaft 41 which passes thru a one-piece cylindrical housing 43 and carries at its free end a sprocket Wheel 44, receiving its power from a prime mover (not shown) by means of a. chain 46. The housing 43 at its inner end has an extended ilange 47 which is secured to the base by means of bolts 49, there being a gasket 50 between the housing and base in order to make a fluid tight connection since it is desired that the bearings 52 for the shaft, the bearings 18 and the pinion 40 shall all rotate in an oil bath in order to provide proper lubrication for the device. Ob-

viously the movement of the pinion 40 thru the oil bath will provide proper lubrication for the teeth of the bevel gear even tho the level of the oil should drop below the axis of shaft 41.

The annular Vupsftanding 'flange 21 carried by, and preferably integral with' the drive ring 20, obstructs the passage of m'ud -two lugs.

sprocket wheel 44. The outer hub of this sprocket wheel is provided with a number of small cylindrical holes 60 to receivea turn bar so that the shaft 41 may be turned thru a small angle with- -out applying power to the device.

In conformity with modern safety requirements I prefer to enclose the sprocket wheel and chain and for this purpose I mount on the pivot 56 a hood 62 having an inner opening 63 for the dog and having in the outer face an arcuate slot 64 for reception of the turn bar when used with one of the holes 60. The hood or cowl 62 may be thrown back about its pivot as shown in the dotted lines in Figure 2 when it is desired to remove the sprocket wheel 44 or for any'other purpose.

The table bushing is, in accordance with ordinary practice, in two pieces and each has l number of lugs '72. fittingA in correspondingly shaped recesses 71 in the drive ring 20, vthe upper rface of which lies in the same horizontal plane as the top of the table bushing, the gear ring 22 and the mud plate 37. The table bushing has a conical skirt 73 fitting snugly but not rotatingly on theconical surface 74 of the drive ring since these parts can never rotate with respect to each other vwhen the table bushing is in lowered position. The table bushing also has a central coni- 1 cal opening 75 substantially parallel and coaxial surfaces servingin the usual manner to receive the ordinary wedge blocks (not shown) to hold the drill-stem when so desired. 1

Within the table bushing there is a gripping device composed of two similarhalves 78, each having therein a triangular prism, wedge block 79 each having a plurality of rounded lugs 80 received within an elongated recess 81 in the bush- 1 ing which opening rather snugly receives the The blocks 79 are pivoted as by means of a rod 83 but this rod vts the blocksrather loosely, and takes no wear, having for its sole function the prevention of loss of the wedge 1 blocks 79. In use the wedges push with their rounded noses 82 into a rounded recess 84 of the gripping sections 78, which movement is permitted by the loose t of their pivots.

'I'he gripping sections each have mounted 1 therein a plurality of Yconcave faced rollers 88 journaled on pins 89 and arranged in pairs vertically disposed with respect to one another as best seen in Figure 2. 'I'hese rings or wheels 88 afford no resistance to upward or downward movement 1 of the drill-stem 90 but as explained a little later engage the drill-stem to rotate it in case the bushing 78 is rotated. I find it advisable to support the gripping device 78 on the table bushing 70 by anti-friction devices and for this purpose I use conical rollers 92 mounted on pins 93 and rolling on a conical seat 94 at the top of the bushing skirt 75.

When the end Walls of the recesses 81 in the table bushing 70 engage the rounded ends 80 of inward against the half sections 78y and thus cause these two portions of the gripping base to move toward one another, that is radially inward against the pipe 90, and thismovement naturallyv causes an increase in pressure of the gripping rollers 88 against the drill stem. This action is.

very similar to that of a toggle as the harder the resistance to turning, the greater the hugging action of the two members 78 on the stem. The gripping rollers having concave faces fit the stem and being pushed substantially radially by the wedging blocks give a greatly increased area of contact over the ordinary gripping rolls which bite into the stem on the edge only of the rolls.

The drive ring and the gear ring 22 each have cooperating slots 95 and 96 respectively which receive the blocks 97 which seat in a diagonal manner best shown inFigure 1 but which may be lifted bodily out of the slots and placed in neutral position in the slot 96 which is of a length to receive the .block 97 to hold it out of contact with the drive ring 20.

With the blocks 97 in neutral position rotation of the pinion will cause the gear ring to rotate without moving the drive ring, this action being convenient for screwing and unscrewing pipes and for other purposes. In such use I nd it convenient to afford a positive lock for the drive ring and I therefore slit the base as at 100 and mount therein a brake shoe 101 which can be moved radially by any desired mechanism for example, the screw 102 having an elongated head 103 to one side of the base for convenience of operation. By advancing the screw 102 by meansl of a crow bar placed in the holes of the head 103 the shoe will be brought into frictional contact with the skirt 14 and by reason of the low pitch threads on the screw 102 the brake shoe may be ylocked in any desired position, this locking brake being a safety first feature to prevent unscrewing of a portion of the drill beneath the table level..

. In Figure 5 I have shown a much simpler form, one that does not provide for the convenience of disconnecting the drill-stem as. shown in the preferred form. In this form the gear, gear ring and drive ring are all integral, this unied element being denoted by 110 having a at top 111 flush with the remainder of the table, having a skirt 112 engaging the bushing and also the base, and having an annular groove 114 near the top cooperating with a groove 115 in the hold-down ring 116 to provide an annular mud uid receiving chamber 117, this chamber having an annular entrance mouth 118 formed by the gap between the gear ring and the hold-down ring and discharging thru a drain pasage, 120 to a vertical discharge passage 121 caused by a bend or ridge in the apron or skirt of the bushing. In this modification the mud fluid spreading radially outward over the top of the rotary passes thru the annular opening 118 and is defected downward by the vertical ange 122 -on the hold-down plate 116 thereby causing the discharge of the mud and sand-laden fluid toward the passage 121 instead of radially outward where this fluid would injure the gear.

In Figure 6 the backup post foot hole 140 drains into the cavity between the drive ring 141 andthe gear ring 142, the drive ring having a drain opening 144 leading to the annular drain channel which is similar to that of the modification shown in Figure 5, and discharging into the central well' opening` as in that modicatlon. In the modification of Figure 6, however, the hold-down ring 150 engages the gear 151,-but does not extend to a level with the top of the table, and a mud ring 154 is therefore mounted on the gear ring and is dome shaped so as to discharge the mud fluid about centrally of the hold-down ring and to one side of the upstanding flange 155.

The operation of the device is as follows: The housing is filled or partially filled with oil preferably thru the hole 130 on top of the box or housing, which hole is then closed by means of the plug 131. When the gear ring, that is the parts permanently secured together to revolve with the large bevel gear, is rotated by the drive pinion, the bushing by the locking connection with the drive ring and the locking connection between the drive ring and the gear ring, moves but the automatic ring gripping device remains free for an instant as does the drill-stem, but the slight friction of the stem caused by contact with anyone of the concaved faced rings tends to retard the rotation of the two halves of the gripping device, making this device for a very brief interval of time relatively stationary with respect to the table bushing, which is now revolving and in its movement pushes one o'f the rounded lugs of the triangular wedging blocks, causing the block to advance toward the stem in substantially a radial direction, and since the other half of the gripping device is acted upon by exactly the same force the two sections are pushed toward one another so as to grip firmly the stem and to turn it. Obviously during the rotating movement the drill-stem by gravity slowly works downward, this movement receiving no opposition from any part of the rotary including the gripping elements.

In order to make or break a joint with the machine the' drill-pipe is raised until the coupling just beneath the gripping device is brought against the bottom of the gripping device. Continued raising of the pipe lifts the gripping device out of the table bushing, since the joint is of considerably greater outside diameter than the pipe itself. When the pipe joint has been raised to a convenient height above the flat top of the' rotary the gripping device in the meanwhile having been removed by lifting one half vertically upward, the ordinary conical wedges are seated in the conical apron or skirt of the bushing and by biting into` Another wrench is placed just above the joint of l the pipe and thehandle of this wrench is then set against the drive post placed in hole 142 of the gear ring.

The locking blocks 97 are now each lifted out of their diagonal locking position and are placed in neutral position to free the drive ring from the gear ring. The brake shoe is now firmly seated against the outer cylindrical periphery of the apron or skirt of the drive ring holding the -latter stationary with respect to the base. The prime mover, motor, steam engine, or whatever it may be, is now started, turning the table in a counter clock-wise direction. The post in hole 142 will now turn the upper section of the pipe while the lower section of the pipe will remain stationary by reason of the locking of the drive. ring tothe base and consequently the joint will be separated or unscrewed. In scewing up sections of pipe the process is merely reversed. The lower section of the pipe is always' held stationary due tothe danger of unscrewing a joint below the rotary in case the lower portion of the stem should be held stationary by friction in the drilled hole.

What I claim isz- 1. In a rotary, the combination with a base and a circular table having a peripheral edge, of a hold down ring having means to engage the base, means to engage the table thru its entire periphery and means surrounding the table and overlapping the hold down ring to guide mud from the top face of the table away from the peripheral edge of the table.

2. In a rotary, a gear table, a base having an annular oil chamber, a shaft housing secured to said base and having' an oil chamber therein communicating with said annular chamber, a shaft Within said housing, a pinion on said shaft and rotating in part in the annular chamber, a gear on said table meshing with said pinion,.a plurality of bearings all located in part in said annular chamber rotatingly supporting said table on said base, said parts being so located that mud from the top face of the table is discharged toward and into the drilled opening, and means for guiding the mud from said gear and bearings.

3. In a rotary, the combination with a basef and a table rotatably mounted therein, of a brake member secured to the base and means to apply the brake member against the periphery of the table to frictionally lock the table against movement with respect to the base.

4. In a rotary, an annular gear, a drive ring,

4and an annular upstanding flange carried by said drive ring for obstructing the mud fluidseeping between the gear and ring from passing toward the gear teeth.

5. In a rotary, a base having an annular oil chamber therein, a plurality of bearings located in part in said chamber, a table resting upon said bearings and having an annular mud drain l therein, an annular gear on said table depending' into said chamber, and a hold-down ring overlying the peripheral edge of said table and having an upstanding ange for directing matter away from said bearings, said table having a passageway therein draining said mud away from the oil chamber and to the drilled hole.

6. In a rotary, a unitary housing, a drive shaft therein, axially spaced bearings for rotatably supporting the drive shaft in the housing, a gear on said shaft at one side of said housing, and means carried by said housing engaging said gear to lock said shaft to the housing.

'7. In a rotary, a base, a gear ring rota ly mounted within saidbase, an annular hold-do ringsecured to said base and overlying a portion of said gear ring, and an annular vertical flange on said hold-down ring for deflecting mud laden fluid from said gear ring.

8. The device of claim 7 in combination with means for deflecting said mud laden fluid outwardly of said flange. A

9. The device of claim 1 in which the hold down ring and the mud guiding means are integrally connected.

10. In arotary machine for drilling'wells, the combination of a base having a vertically extending 4annular flange, a gear rotatably supported .within said base, an annular hold-down ring secured to said annular flange and overlying a portion of the gear ring to define an enclosure' forl the gear .teeth onsaid gear ring, and an annular vertical fiange on said hold-down ring for deflecting mud-laden fluid from said gear ringf 11. In a rotary machine for drilling wells, th

icombination of a base having a vertically extending annular flange, a gear ring rotatably supported within said base, an annular hold-down ring secured to the annular flange and overlying a portion of the gear ring, means defining a labyrinth clearance between the hold-downring and the gear ring to resist the entrance of mud-laden uid into the base. h

12. In a. rotary machine fr drilling wells, the combination of a base having a vertically extending annular enclosure fiange, a gear ring rotatably supported within said base, a hold-down ring secured to the annular enclosure flange and overlying a portion of the gear ring, means on the gear ring defining an inverted annular channel, and an annular ridge on the hold-down ring extending upwardly into said inverted annular channel.

13. In a rotary machine, the combination of a base, a rotary table rotatably supported in the base, the base being provided with an outwardly 95 extending pinion shaft supporting portion, a unitary pinion shaft housing supported thereby, a pinion shaft rotatably supported within the holising, axially spaced bearings for rotatably sup- 'porting the pinion shaft, means carried by the shaft and adapted to drive the rotary table, locking means non-rotatable relative to the shaft and supported on the shaft, and means can'ied-by the housing to engage the locking means and hold the pinion shaft from rotation.

g 14. In a rotary machine, the combination of a base, a rotary table rotatably supported in th base, the base being provided with outwardly extending pin'iim shaft supporting portion, a unitary pinion shaft housing supported thereby, a pinion shaft rotatabllggsupported within the housing, axially spaced arings in which the pinion shaft is journaled, drivemeans carried by the shaft and adapted to drive the rotary table, locking means non-rotatable relative to the shaft and 115 mounted on the shaft, a swinging locking pawl carried by the housing to engage the locking means, and hold the pinion shaft from rotation.

' 15. In a rotary machine, the combination of a ..base, a unitary pinion shaft assembly carried by extending annular rim` on the base cooperating with the table to form a complete enclosure around the table and gear, an opening in the rim, the 12g unitary pinion shaft assembly including a housing, a pinion shaft rotatably supported within the housing on` axially spaced bearings, drive means secured to the inner end of the pinion shaft to engage and drive the gear carried by the rotary table, and means carried by an outwardly extending end of the shaft for driving the shaft,the unitary pinion shaft assembly being adapted to bev assembled as a'unit over the .opening in the rim so that the drive means carried by the shaft is inserted radially into the base through the opening in the rim thereof, and .the housing being adapted to cooperate with the to-close the opening in the base to forma fluid-tight connection between the base rim and the housing.

16. In a rotary machine, the combination of a base, a unitary pinion shaft housing carried by the base and having spaced bearings, a rotary table carried by the' basean'd including a gear, means including a vertically .extending annular 14:5 rim on the base cooperating With the table to form a complete enclosure around said table and gear, an opening in said rim, a lateral extension on the base having an opening coextensive with the opening in the rim, means for connecting the housing with the lateral extension to close the opening in the extension and to maintain an oiltight seal therebetween, a pinion shaft journaled in the spaced bearings of the housing and extending radially with relation to the rotary table and mounted within the housing, a pinion at one end of the shaft in driving connection with the gear on said table, saidgear being adapted to be inserted into driving relation with the gear of the table through the opening in the rim and to be withdrawn with the pinion shaft and housingA as a unit from the base, and means on the other end of the shaft for driving the shaft.

17. In arotary machine, the combination of a base, a rotary table carried by the base and including a gear, means including a vertically extending annular rin on said base cooperating with the table to form a complete enclosure around the table and gear, an opening in the rim, a lateral extension on the base having an opening coextensive with the opening in said rim and terminating with a flange `face, the base being provided with an outwardly extending pinion shaft supporting portion, a unitary pinion shaft unit mounted on said portion of the base, said unit comprising a unitary bearing housing having axially spaced bearings near the ends thereof, and a radially extending iiange cooperating with the ange faceon the base to close the opening in the lateral extension of the base, a pinion shaft rotatably supported by the bearings, a pinion on one end of said shaft for driving the rotary table and removable through the opening in the base extension andrim, and means to drive the pinion shaft.

18. In a rotary machine, the combination of a base, a rotary table carried by the base and including a gear, means including a vertically extending annular rim on the base cooperating with the table to forma complete enclosure around the table and gear, an opening in the rim, a lateral extension on the base having an opening coextensive with the opening in the rim and terminating -with a ange face, a unitary pinion shaft bearing housing aligned radially with the axis of the table and engaging with opposed parallel ways on the base, meansA for detachably securing said housing in position on said ways, said housing having an inwardly facing flange cooperating with the flange face on said base extension to close the opening in the base extension and the rim, means to maintain an oil-tight seal between the opposed flange faces, bearing means in the unitary housing to rotatably support a pinion shaft, a

. 'pinion on one end or said shaft within the said enclosure in driving connection with the gear on the table, and means to drive the shaft.

19. In a rotary machine, the combination of a base, a rotary table including a gear carried by said base, means including a vertically extending annular rim on the base cooperating with the table toform a complete enclosure around the table and gear, an opening in the rim, a lateral extension on the base having an opening coextensive with the opening in the rim and terminating with a flange face, a pinion shaft assembly including a shaft, means to drive said shaft, a pinion insertable through the opening in the extension and rim and in driving connection with the gear on the table, a one-piece support for the pinion shaft assembly having axially spaced bearing for supporting the shaft, one end of the support having a flanged face cooperating with the iiange face on the base extension-to close the opening therein, and means to secure said support in axial alignment with the table including opposed parallel ways on which said support is mounted.

v20. In a rotary machine, the combination of a base, a rotary table including a gear ring carried by the base, the base having an outwardly extending portion and a vertically extending annular rim an opening in the rim, a unitary pinion shaft assembly adapted to be removably supported on the outwardly extending portion of the base, saidv assembly including a housing, means for removably securing the housing'over the opening in the rim, a pinion shaft supported within the housing, vXally spaced bearings within the housing for rotatably supporting the shaft, a pinion supported on the inner end of the shaft in position to mesh with the gear carried by the table, means secured to the pinion shaft'for driving the same, said pinion shaft assembly adapted to be mounted on the extension ofthe base axially with respect to the rotary table so that the pinion passes through the opening in the rim'in position to mesh with the gear ring as a unit.

2l. In a rotary, a base, a table rotatable therein, and a hold-down ring secured to said base and overlying the periphery of the table, the upper faces of the ring and table lying in the same horizontal plane. A l

22. The device of claim 21 in which the table carries a bevel gear and the ring overlies the entire edge of the gear. Y

23. In a rotary machine, the combination of a base, a table rotatably supported by the base, the base having a circumferentially extending flange, a hold-down bracket in the form of a ring mounted on and secured to the ange, the rotary table having'gear teeth formed on its under side under the hold down ring, the hold-down ring having an annular ange which extends into a circumferential recess formed in therotary table above the gear teeth in position to engage the bottom surface of the recess in the table.

24. In a rotary machine, the combination of a base, a table rotatably supported by said base, aunitary housing secured to said base, a pair of bearings, the bearings being supported in said unitary housing near each end thereof and said bearings being relatively axially spaced, said unitary housing holding said bearings in true axial alignment, a pinion shaft carried by said bearings, a pinion on one end of said pinion shaft for driving said table, and drive means on the other' vend of said pinion shaft.

25. In a rotary machine, the combination of a base, a table rotatably supported by said base, a

unitary housing secured to said base, aligning means cooperating between said base and said unitary housing for maintaining said unitary housing in aligned position on said base, a pair of bearings, the bearings being supported in said unitary housing nea each end thereof and said bearings being relatively axially spaced, said unitary housing holding said bearings in true axial alignment, a pinion shaft carried by said bearings, a pinion on one end of said pinion shaft for driving said table, and drive means on the other end of said pinion shaft. Y

26'. In a rotary machine, the combination of a base, a table rotatably supported by said base, a unitary housing secured to said base, shoulders cooperating between said base and said unitary housing for maintaining said unitary housing in aligned position on said base, a pairof bearings,

the bearings being supported in said unitary housing near each end thereof and said bearings being relatively axially spaced, said unitary housing holding said bearings ,in true axial alignment, a pinion shaft carried by said bearings, a pinion on one end of said pinion shaft for driving said table, and drive means on the other end of said pinion shaft.

` 27. In a rotary machine, the combination of a base, a table rotatable on said base, a unitary housing adapted to be secured to said base, a pair of axially spaced bearings carried by said unitary housing near the ends thereof, said bearings being rigidly retained in such relative positions as to be on the same axis, and aligning means cooperating between said base and said unitary housing for maintaining said unitary housing in such a position that the axis of said bearings will intersect the axis on which said table rotates.

28. In a rotary machine, the combination of a base, a table rotatable on said base, a unitary housing adapted to be secured to said base, a pair of axially spaced bearings carried by said unitary housing near the ends thereof, said bearings being rigidly retained in such relative positions as to be on the same axis, and rigid shoulders cooperating between said base and said unitary housing for maintainingsgaidunitary housing in such a position that the axis of said bearings will intersect the axis on which said table rotates.

29. In a rotary well drilling apparatus, the combination of a base, a rotary table vertically journaled on said base, a horizontally disposed selfcontained pinion shaft unit aligned radially with the axis of said table, said unit comprising a unitary bearing support engaging in opposed parallel ways in said base and having two axially spaced bearings supported therein on a common axis, a pinion shaft journaled in said bearings,

and a pinion secured on the inner end of said shaft and in driving connection with said table; and means for detachably securing said unit in position in said ways.

30. In a rotary well drilling apparatus, the combination of a base, a rotary table vertically journaled on said base, a horizontally disposed spaced bearings supported therein on a common axis, a pinion shaft journaled in said bearings, and a pinion secured on the inner end of said shaft and in driving connection with said table, means for detachably securing said unit in position in said ways, and means for locking the pinion shaft against rotation.

31. In a rotary well drilling apparatus, the combination of a base, a rotary table vertically journaled on said base, a horizontally disposed self-contained pinion shaft unit aligned radially with the axis of said table, said unit comprising a unitary bearing support engaging in opposed parallel ways in said base and having two axially spaced bearings supported therein on a common axis, a pinion shaft journaled on said bearings, and a pinion secured on the inner end of said shaft and in driving connection with said table, means for detachably securing said unit in position in said ways, and a driving means supported on the outer free end of said shaft.

32. In a rotary machine, the combination of a base providing a vertical bore, a table rotatably mounted on the base in the bore, the base providing an outwardly extending portion, a housing, axially spaced bearings mounted entirely within the housing, a pinion shaft journaled on the bearings, means for removably securing the entire housing to the outwardly extending portion of the base so that the bearings and shaft are removable with the housing as a unit from the base, a pinion gear secured to the shaft at one end to mesh with gear teeth formed on the table, and an overhanging sprocket secured to the-opposite e'nd of the pinion shaft.

33. In a rotary, a base, a gear table rotatably mounted within said base, a gear housing secured to the base, a hold-down ring secured to said gear housing and abutting said gear table above said gear, and means removably secured to said gear table and overlapping said hold-down ring horizontally and vertically whereby mud fluid is prevented from flowing between the said means and the hold-down ring and entering said gear housing.

' VICTOR W. ZILEN. 

